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Poster: Frank Panucci Date: Aug 23, 2012 4:27pm
Forum: prelinger Subject: Pulldown in this year's uploads?

First, off, great work on the huge number of 2012 uploads. The recent videos are entertaining and often useful.

Question: Is there any info about the pulldown cadence of these files? They seem sort of random. I've loaded several into a video editor, and examining each frame for interlace appears to yield results such as (for instance) 2:1:1:3:1:4:1:1:1:1:2:2 and so on. The results vary greatly. I am baffled. I've worked with video professionally for a long time, but I've never seen files quite like these.

The videos play back acceptably with VLC, and look good on TV when burned to DVD. They work well in those contexts. However, the MP4 intraframe compression is BRUTAL. The old MPEG2 files, despite occasionally reduced horizontal resolution, offered much cleaner frames in terms of breaking them out - also, they were straight 3:2 pulldown, which made rebuilding 24fps sequences foolproof and easy.

I've re-purposed a few short sequences from the recent files with a workaround. I break the frames out with after effects, using a setting that mostly eliminates interlace artifacts, but gives me one repeated frame which is blurry and apparently takes the place of the frame that should be there. I load that sequence into Xnview and select the "blurry" column of thumbnails and delete those frames. I use a sequence renamer to renumber them in order. I now have a shot that has a missing frame every three to five frames, depending on the vagaries of its encoding. Sometimes that is actually acceptable as-is with animated shots. For live action, I'm experimenting with the Twixtor plugin, set with keyframes, to, as much as possible, rebuild the missing frames. That method is promising, but I'm trying to make it faster to set up.

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Poster: Frank Panucci Date: Oct 3, 2012 2:18pm
Forum: prelinger Subject: Re: Pulldown in this year's uploads?

Oy. Earlier in the year I had success transferring a few of these to DVD, but I guess I got lucky and picked "good" ones. I just dumped a large load of these 2012 uploads to disc. Results varied greatly from file to file, but half or more of them just "didn't work". The DVD encoders (I tried several) apparently couldn't make sense of whatever interlace thing is going on with them, and there were doubled frames and mushy artifacts abounding. The problem remains a mystery...

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Poster: Scribble Date: Dec 22, 2012 7:53pm
Forum: prelinger Subject: Re: Pulldown in this year's uploads?

I've been having similar results, a few videos actually worked quite well after removing pulldown, but the majority are just as you describe, mushy weird frames in between 3 or 4 nice, solid ones...

Please keep us up to date with your efforts, I think there is probably some way to write an expression in after effects that will remove frames in any way you desire, but I don't know much about expressions...

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Poster: Frank Panucci Date: Dec 24, 2012 10:36am
Forum: prelinger Subject: Re: Pulldown in this year's uploads?

No automation yet. So far, I'm simply identifying which sequences I need, and isolating frames semi-manually as described above. I don't want to complain at all, though, because free is good. Lots of this footage is very useful. Some clients want seldom seen retro imagery. The extra effort required to properly derive clean shots from most of 2012's uploads makes it less likely others will go to the trouble, so the footage I use is potentially more unfamiliar to a client's audience.

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Poster: Frank Panucci Date: Aug 22, 2013 5:04pm
Forum: prelinger Subject: Re: Pulldown in this year's uploads?

Update: The TONS of otherwise wonderful Prelinger uploads from the last nine months also suffer from the problems I mentioned above. That's too bad. Re-encoding that many files properly and re-uploading would take a huge, frustrating amount of time. Do-overs are no fun at all.